1. Field of the Invention
This invention relates to a detergent resin composition used for deterging the inside of molding machines used for mold-processing vinyl chloride resin, vinylidene chloride resin, chlorinated polyethylene, etc.
More particularly it relates to a detergent resin composition having blended therein, a polystyrene resin, a polymethyl methacrylate resin and a neutral salt of sulfonic acid, each in a specified quantity, and further, basic magnesium carbonate, magnesium hydroxide, aluminum hydroxide or zinc carbonate or a mixture of two kinds or more thereof, in a specified quantity.
2. Description of the Related Art
In the mold-processing fields of plastics, production of more and more kinds of plastics each in a small quantity has been intended; thus the frequency of resin or color exchange inside molding machines has been increasing.
In particular, chlorine-containing polymers such as vinyl chloride resin, vinylidene chloride resin, chlorinated polyethylene, etc. are easily thermally decomposed and adhere to the inside of molding machines to form black or other colored pyrolyzed contaminants which adhere to the inner wall or screw of the molding machines; thus, a process of drawing out the resulting contaminated screw and brushing the screw and the inner wall of the cylinder of the molding machines has been employed. According to the process, however, a drawback exists in that a long time is required for completely deterging the inside of molding machines and hence the time loss is large. Thus, in order to solve these problems, various detergents for deterging the inside of molding machines have been developed. For example, a detergent, rust proof composition having an inorganic filler, a stabilizer and a lubricant blended in a vinyl chloride resin has been proposed (Japanese patent application laid-open No. Sho 60-110413). However, this detergent, rust proof composition has drawbacks that the composition is insufficient for removing the preceding chlorine-containing resins such as vinyl chloride resin, etc. adhered to the inner wall or screw of molding machines and is difficult to peel it off. Further, the vinyl chloride resin contained in the detergent, rust proof composition is thermally decomposed and remains inside the molding machines and the resulting burnt resin becomes a contaminant, which, in turn, contaminates the succeeding molded product.